Question

Consider the following statements (i)-(iii), each with one or two blanks. Which of the following options gives the correct answers for the respective blanks marked (1) to (4) in the statements?
(i)Bones have a hard and non-pliable ground substance rich in ___(1) and ___(2) which give the bone its strength.
(ii)Some of the columnar or cuboidal cells become specialized for secretion and are called ___(3) epithelium.
(iii)___(4) junctions help to stop substances from leaking across a tissue.

(a)(3) glandular (4) tight
(b)(1)calcium salts (2)collagen fibers (3)compound (4)excretory
(c)(3)glandular (4)Adhering
(d)(1)magnesium salts (2)elastic fibres (3)compound

Answer 1

Hint: Bone is a connective tissue present in the body to provide a framework and strength. It is made of various compounds, where the main compounds are a non-metallic mineral and a structural protein.

Complete answer:
- Bones have a hard and non-pliable ground substance rich in calcium salts and collagen fibers which give the bone its strength.
- Some of the columnar or cuboidal cells become specialized for secretion and are called the glandular epithelium. An example of this epithelium is the endocervical glandular epithelium that is present in the reproductive tract to provide lubrication.
- Tight junctions help to stop substances from leaking across a tissue. The junctions join together the cytoskeleton of the adjacent cells.

Additional Information: - Exocrine and endocrine glands of the body are made of a particular kind of tissue aiding in the secretion of various substances.
- Particular junctions present between cells help in leaking across tissue and also seal the paracellular pathway.
- Four types of cells are formed within the bone tissue: osteoblasts, osteocytes, osteogenic/hematopoietic cells, and osteoclasts.
- Special cells are present on glandular epithelium known as goblet cells.
- Tight junctions are also known as zonulae occludentes or occluding junctions. These junctions include approximately 40 different transmembrane and cytoplasmic proteins.

So, the correct answer is ‘(3) glandular (4) tight’.

Note: - Bone is the hardest connective tissue. There are 206 bones in the adult human body, excluding the teeth and the sesamoid bones.
- Different types of connective tissue include various types of fibrous tissue, bone, blood, ligaments, tendons, cartilage, and adipose (fat) tissue.
- Tight junctions are present in mostly all vertebrates except the Tunicates.